This invention relates to an interrupter for a multisection AC capacitor, and more particularly to an interrupter for a round dual-section AC capacitor.
Dual- or multisection AC capacitors are often used for AC motor-start or motor-run service. Failures of such capacitors generally are the result of pressure buildup within the capacitor. Various safety devices including circuit interrupters have been incorporated into such capacitors to render them inoperative when the pressure builds up.
Generally, these interrupters are non-flexible plates through which the ends of the terminals extend. Electrode tabs from the capacitor or capacitors are attached to these terminals beneath the plate. When pressure builds up in the unit, the cover starts to dome or bulge pulling the terminals away from the plate and causing the electrode tabs to become disconnected from the terminals and disconnecting the unit.
These capacitors are generally oval in shape, particularly those employing three terminals. When round units have been used, they have generally been larger than 2.5 inch (63.5 mm) diameter. In the former design, the terminals have been arranged in a line along the long axis that is also the crest of the dome or bulge resulting from pressure buildup. With round units, the terminals are offset from this crest line, and therefore in an area of less deflection. In order to insure that at least two of the three terminal-tab connections are broken in response to the same pressure buildup even though less cover deflection, spacers have been used between the interrupter and cover so that the required disconnection will result even with less vertical movement.
The problem becomes more acute when the terminals in a round cover must be spaced farther away from the center in order to meet Underwriters Laboratories minimum spacing requirements as described in copending application Ser. No. 238,314, filed Feb. 26, 1981, of which this application is a continuation-in-part.